Ratings for NBC’s London Olympic primetime coverage are on a roll — and setting records.

Saturday’s primetime drew a 18.0 overnight, which translates into 18% of households in the 56 urban TV markets measured for overnights. That’s the highest overnight ever for the first night of competition in a Summer Games held outside the U.S.

That 18.0 overnight is also up 8% from the 2008 Beijing Summer Games – which had live primetime coverage in the East Coast and Central time zones — and is 22% above comparable coverage of the same night of the 2004 Athens Olympics.

The rest here.

As much as I personally hate the format of tape-delayed events in primetime, it seems to be working. And if I had to guess, they’ll continue to get good numbers as we get to the more popular events.